Electronic antitheft system

ABSTRACT

An electronically controlled lock assembly for a chamber door adapted to afford access to the chamber only to those who carry a passkey having a predetermined profile. Mounted on the door is a keyway having a group of electric switches therein which are selectively actuated by the inserted passkey in accordance with the profile thereof. The door is provided with a signal-operated locking mechanism which is activated to release the door lock only when an output signal is applied thereto. Disposed within the chamber is a logic circuit which is connected to the group of switches in the keyway to establish an electrical test pattern depending on which of the switches is activated and hence on the profile of the passkey. The logic circuit includes a switching panel operating in conjunction with an insertable coded reference key to produce a reference pattern depending on the key code, the logic circuit comparing the reference and test patterns to produce a control signal only when the patterns are coincident. The control signal is applied to an output circuit connected to the locking assembly to produce an output signal for releasing the lock.

United States Patent Inventor Gerald M. Goldman 185 Bronx Road, Yonkers, N.Y. 10704 Appl. No. 864,801 Filed Oct. 8, 1969 Patented Dec. 28, 1971 ELECTRONIC ANTI'IIIEFT SYSTE Primary Examiner-L. T. Hix Attorney Michael Ebert ABSTRACT: An electronically controlled lock assembly for a chamber door adapted to afford access to the chamber only to those who carry a passkey having'a predetermined profile. Mounted on the door is a keyway having a group of electric I switches therein which are selectively actuated by the inserted passkey in accordance with the profile thereof. The door is provided with a signal-operated locking mechanism which is activated to release the door lock only when an output signal is applied thereto. Disposed within the chamber is a logic circuit which is connected to the group of switches in the keyway to establish an electrical test pattern depending on which of the switches is activated and hence on the profile of the passkey. The logic circuit includes a switching panel operating in conjunction with an insertable coded reference key to produce a reference pattern depending on the key code, the logic circuit comparing the reference and test patterns to produce a control signal only when the patterns are coincident. The control signal is applied to an output circuit con nected to the locking assembly to produce an output signal for releasing the lock.

PATENTEnnmzs I97! 31331; 301

' sum 1 0F 3 v2/1) LOG/C o OUTPUT 253 O CIRCUIT CIRCUIT SOLE/VOID ELECTRONIC ANTITI-IEFT SYSTEM Most locks in use today are of the tumbler type. This is so despite the fact that tumbler locks are easily picked or compromised by a master key. At best, these devices act to disuade rather than deter a thief. The growing crime rate in stolen automobiles, home burglaries, thefts in public accommodations, and hijacked trucks bears testimony to the fact that there is a strong felt need for an inexpensive system which cannot be compromised or jimmied open. The present invention fills that need.

Whereas in the past, a door was only as strong as its lock, the present system provides a lock whose strength is only as strong as its door. This has been accomplished by separation of the locking function from the sensing function. In an ordinary tumbler device, the tumblers act to both sense the key and unlock the system. Thus, it was a common fact that a well placed screwdriver could snap the tumblers. and destroy the latching mechanism. This invention places the lock behind the door where it is safe from burglar instruments. The sensing keyway is placed in front of the door as always, but if attempt is made to pick or jimmy the keyway, only the keyway is destroyed...the lock will not open. By employing the present principle, the lock may be built into walls, cabinets, or behind partitions which are beyond reach of burglars.

The invention has many novel features in the art of locks. In the first instance, the present system has fashioned an electronic lock which uses logic circuitry to sense the insertion of the correct key into the keyway. Secondly, the present system allows for easy mass-production of the insert which sets the combination and the key by stamping both parts together in the same operation. The lock combination can be periodically changed without any bother by changing the insert and the key. Third, the present system is extremely low cost, unlike most of the other electrical devices on the market today. Fourth, there isno known master key which will thwart or bypass the sensing apparatus, and activate the lock release.

Attempts have heretofore been made to use a sensing panel to determine the insertion of the correct key 'in the keyway. Although a system of this type endeavors to carry out many of the objectives of the present invention, it is not capable ofachieving the basic objective of sensing only the correct key. It has been found that the sensing circuitry can be bypassed by a master key arrangement so that the relay will activate the lock release. In addition, this system has many other shortcomings, and lacks many of the advantages of the present device.

The present invention uses logic circuitry which will work every time under the proper conditions to set or release the lock and/or sound an alarm. The aforementioned system by comparison cannot activate an alarm system in all cases where an incorrect key is inserted into the keyway.

It has now been discovered that an electrically activated lock can be constructed to' have a simple means of presetting its combination, and when the correct key is inserted, the output circuitry will be activated.

It is a primary object of this invention to provide a lock that cannot be picked or jinimied or compromised.

It is another object of this invention to provide a lock that can be easily mass produced.

It is one other object of this invention to provide for a simple means of setting the combination of the lock.

Another object of this invention is to provide for a simple means to reset the combination in case of loss of key.

It is still another object of this invention to provide for an alarm if an incorrect key is inserted into the lock.

One other object of this invention is to provide for a sensing apparatus within the lock that has no moving parts.

It is another object of this invention to provide for the key and insert to be made in one simple operation.

It is still another object of this invention to provide for a lock that has no precision parts or components with high tolerances.

It is but one other object of this invention to provide for the sensing apparatus and the output release unit to be mechanically independent of each other so that breaking the sensing apparatus will not cause release of the output unit.

" The foregoing as well as other objects of this invention will become apparent with reference to the detailed description below, taken in conjunction with the attached drawings in which:

FIG. lis a block diagram of the lock mechanism.

FIG. 2 is an electrical diagram of the lock.

FIG. 3 is an electrical diagram of the output unit of the electrical circuit.

FIGA is an electrical diagram of the output unit of the electrical circuit with the addition of an alarm.

FIG.'5 is a variation of the electrical diagram of FIG. 2.

FIG. 6 is a variation of the electrical diagram of FIG. 4.

FIG. 7 is a top view of a keyway for this lock. FIG. 8 is an end view of a keyway for this lock.

FIG. 9 is a top view of a key for this lock. FIG. 10 is an end view of a key for this lock. 7 FIG. 11 is a top view of a switch panel for this lock.

FIG. 12 is an end view of a switch panel for this lock.

FIG. 13 is a top view of an insert for the switch panel.

FIG. 14 is an end view of an insert for the switch panel.

Generally speaking, the invention relates to a method and apparatus for an antitheft system. A first and second means i are provided for producing an electrical combination, respectively. The two electrical combinations are then compared to determine if they match each other. An electrical signal is produced as an indication of this comparison which activates a switching means that is responsive to and operative as a function of the comparison.

The systemcontains a keyway having a plurality of switches and/or contacts. When the key is inserted into the keyway an electrical combination is produced by the selective contacts which only that particular key will make. The keyway is electronically wired to a circuit having a preset electrical combination which is produced in similar fashion to the keyway, i.e. a particular pattern of contacts are produced. If the insertion of the key makes an identical electrical combination with that of the circuit, a switch is activated. This switch can open a locking mechanism, a solenoid, or other appliance. If the wrong key is inserted, the electrical combinations will not match. Another switch will then activate an alarm if so desired. Only the identical matching of the two electrical combinations will release the lock, which requires the proper key be used.

Now referring to FIG. 1, a block diagram of the lock mechanism is shown. A key 200 is inserted into a keyway 202 through slot 210. The keyway has internal contacts (not shown in this diagram). The key has discrete contact points 201 that make contact with some of the internal contacts within the keyway. The keyway is connected electrically as depicted by arrow 211 to logic circuit 203. The logic circuit contains a switch panel 204, having contact points 205. An insert piece 206 is inserted into the switch panel. The insert piece has discrete plugs 207 which close some of the contacts 205 on the switch panel. The discrete plugs 207 on the insert 206 are an identical match by pattern to those discrete points 201 on the key 200. The logic circuit is able to compare and differentiate between the contact points on the key and those of the insert. The logic circuit is connected to an output circuit 209 as shown by arrow 212. When the above points match, the logic circuit activates the output circuit which supplies power to the solenoid 208 or other output unit as shown by arrow 213. When the points do not match as in the instance when the wrong key is used, the logic circuit will not activate the output circuit. An added feature is circuitry for activating a warning device when the wrong key is used as is described in conjunction with FIG. 4. The above circuitry affords a tremendous manufacturing advantage, since the matching contacts of the key and those of the insert panel can be stamped together on a common die. In the past the loss of a key required a change in the tumblers of the lock. If one loses the key to the above device a new insert and/or matching key can be easily replaced at minimal cost.

Referring to FIG. 2, an electrical diagram of the lock is shown. Diodes through 21 are set up in two logical circuits.

Diodes 10, 12, 14, 16, 18, and 20 constitute one group and 11, 13, 15, 17, 19, and 21 constitute the second group. If current flows through any diode in the first group there will be a voltage drop across resistor 22. A current flowing through any diode of the second group will cause a voltage drop across resistor 23. For maximum positive voltage from point B to A (with switch 2 closed) no current should flow through resistors 22 or 23. In this case the maximum voltage would be the battery 1 potential. Single-pole double-throw (SPDT) switch 24, resistor 30, and diodes 10 and 11 constitute one logical circuit. With switch 24 in the position shown (in contact with diode 10) no current would flow through diode 10, if no positive voltage is applied to point 4. In this state current would flow through resistor 22 if a positive voltage was applied to point 4. With switch 24 in its other mechanical state (in contact with diode 11) no current would flow through diode 11 if the battery potential (point D) is applied to point 4. In this state current would flow through resistor 23 if no potential is applied to point 4. Resistor 30 is needed to complete this circuit. Switch 25, resistor 31, diodes 12 and 13 constitute a second logical circuit; switch 26, resistor 32, diodes 14 and 15 constitute a third logical circuit; switch 27, resistor 33, diodes 16 and 17 constitute a fourth logical circuit; switch 28, resistor 34, diodes l8 and 19 constitute a fifth logical circuit; and switch 29, resistor 35, diodes 20 and 21 constitute a sixth logical circuit, Points 4,5,6,7,8 and 9 are brought out to a keyway (shown in FIG. 7). Switches 24,25,26,27,28, and 29 are mounted on a panel so that they may be set by a single insert (FIG. 11). Switch 2 is brought out to the keyway and is closed by the insertion of the key (FIG. 7 Care must be exercised in choosing Resistors 22,23 and 30-35. If current flows through diodes 11,13,15,l7,19, or 21, due to a lack of positive voltage on points 4-9 (depending on how their respective switches 24-29 are set), the battery voltage will be divided between resistors 23 and any of the resistors 30-35 that are in the conditions to take current. A large voltage drop across resistor 23 is desirable if current flows through any diode (the insertion of the wrong key in the keyway). However, the smaller resistors 30-35 are, the greater the drain on the battery when positive voltages are applied to the combinations of points 4-9. Resistor 23 should also be as small as possible as explained in FIG. 3.

FIG. 3 shows a single-pole single-throw (SPST) relay with coil 40 and contact 41. When no current flows through any diode of FIG. 2, the potential from point B to point A is sufficient to energize coil 40. For this condition to occur the correct key must be inserted into the keyway. With coil 40 energized, contact 41 closes, and power is sent to output 43 which could be a magnetic lock, an automobile solenoid, etc. Points C and D are the power source from FIG. 2, C being the switched power and D being the unswitched power (same for FIGS. 4 and 6). Diode 42 is used to assure that a reverse voltage from points B to A will not energize coil 40. Coil 40 is in series with resistors 22,23, switch 2 and battery 1 in the activate'd state. Resistors 22 and 23 should be as small as possible to allow maximum power to activate coil 40. A fuse can be inserted in series with the relay coil 40 to insure that an excess of current supplied by a voltage greater than that designed for will blow the fuse and not activate the relay. This will thwart any attempt to subvert and bypass the sensing logic of the circuit by an excessive voltage.

FIG. 4 shows an output circuit similar to FIG. 3 with provisions for an alarm if the wrong key or a foreign object is inserted into the keyway. Coil 45 and diode 46 have the same requirements and functions as coil 40 and diode 42 of FIG. 3. This relay which is energized by coil 45 is a double-pole double-throw (DPDT). The normally open contact 47 of one set of contacts 47 and 48 closes when coil 45 is energized and allows power to flow from point C to the output 55. The other set of contacts, normally open 49 and normally closed 50 are wired to a latching relay. The latching relay has a set coil 52 which closes contact 53 and a release coil 51 which opens contact 53. If the correct key is inserted into the keyway, coil 45 will energize, closing contact 49 and opening contact 50. Power will flow from point C through contact 49, through the release coil 51, and contact 53 will remain open (or open if it was closed and the alarm 54 was on). If an incorrect key is inserted into the keyway, coil 45 will not energize and power will flow through the normally closed contact 50, through the set coil 52, and close contact 53 initiating alarm 54. The correct key inserted into the keyway would be required to turn the alarm off.

FIG. 5 works the same as FIG. 2 except that instead of using two diodes, a resistor and a SPDT switch for each logical circuit, one diode, one resistor, and a DPDT switch is used. In FIG. 2, depending upon how switch 24 was set, either diode 10 or 11 is not used. In FIG. 5 diode 70 is shown in the position analogous to diode 10 in FIG. 2. When switch 76 is switched to the bottom set of points, the diode 70 is electrically equivalent to diode 11 in FIG. 2. Switches 77-81 with their respective diodes 71-75 are similar in arrangement to switch 76 and diode 70. Points 64-69 are analogous to points 4-9; resistors 82-89 are equivalent to 30-35, 22 and 23; points A, B, C, and D are the same; and battery 61 and switch 62 are the same as battery 1 and switch 2 of FIG. 2.

FIG. 6 is a variation of the circuit of FIG. 4. Coil and diode 91 have the same requirements and functions as oil 45 and diode 46 of FIG. 4. This relay which is energized by coil 90 is a double-pole double-throw (DPDT). The normally open contact of one set of contacts 94 and 95 closes when coil 90 is energized and allows power to flow from point C to the output. The other set of contacts, normally open 93 and normally closed 92, are wired to a second double-pole relay. The second relay has a coil 98 and two normally open contacts 97 and 99. If the correct key is inserted into the keyway, coil 90 will energize closing contact 93 and opening contact 92. Coil 98 will not energize since contact 92 is open. If an incorrect key is inserted into the keyway, coil 90 will not energize. Current will flow from point C, through contact 92, through coil 98, energizing the coil. Contacts 97 and 99 will close when coil 98 is energized. Current will flow from point D, through closed contact 99 to the alarm. When the incorrect key is taken out of the keyway, current will still flow from point D through contact 97 which is closed, through coil 98. In this state the alarm is still on. The only way to turn the alarm off is to insert the correct key into the keyway. This will open contact 92, deenergize coil 98, and open contacts 97 and 99, turning off the alarm.

FIGS. 7 and 8 are top and end views of the keyway respectively. Metal tabs that are used for contact points can be seen in keyway 109. Points 101 and 105 are points D and C of switch 2 (FIG. 2). Points 101 and 105 can be replaced by a mechanical switch which is activated when the key is fully inserted. This would eliminate the possibility of points C and D being tampered with. Points 102,103,104,106,l07 and 108 are points 4,5,6,7,8, and 9 of FIG. 2, respectively.

FIGS. 9 and 10 are top and end views of the metal key. Slots 116 and 117 are cut out of key 118 with handle 115. Ifthis key was inserted into the keyway of FIG. 7, points 102, 106 and 107 would not make contact with the metal key. The key in this case would have the battery voltage on it, since it is contacting points 101 and 105, which are points D and C in FIG. 2. Therefore, each point that the key contacts will have this voltage applied to it. The handle could be coated with a nonconductor if required. It should also be noted that with a different electrical design the key can have a ground potential on it rather than the voltage that is shown.

FIGS. 11 and 12 are the switch panel. This unit works in conjunction with the nonconducting insert shown top view in FIG. 13 and end view in FIG. 14. Switches 24-29 of FIG. 2 are wired to switches 122, 123, 124, I26, 127 and 128 respectively. Switches are mounted on a nonconducting plate that has insert holes 121 cut into it. The switches are held to the plate at 125. The switches in the normal position are making contact at 129. When the insert of FIG. 13 is snapped into this plate, the switches will be depressed to contact 130, wherever there is an insert plug 137. In the illustration, plugs 131, 134,

and 135 are cutaway. This matches the cutouts of the key in FIG. 9. Plugs 132, 133, and 136 of insert 138 are not cut away. When this insert is snapped into the panel of FIG. 11, switches 122, 126, and 127 will not be affected. Switches 123, 124, and 128 will be forced to their other positions (130). The corresponding switches (for this illustration) 25, 26, and 29 of FIG. 2 are set to contact diodes l3, l5, and 21 respectively. When the proper key for this insert is used in the keyway, the lock would activate. The key shown in FIG. 9 is inserted into the keyway. Points 103, 104, and 108 would have the voltage applied to it. These correspond to points 5, 6, and 9 of FIG. 2. This is the one unique combination where current would not flow through any diode, and the potential from point B to A of FIG. 2 would be sufficient to activate the relay of FIGS. 3, 4, or 6 and send power to the output.

It should be understood that many different modifications can be made to the antitheft unit described and depicted in the attached drawings. The unit described has six discrete points giving a maximum number of combinations of 2=64 (eliminating the cases of all contacts present and all contacts not present the number is reduced to 62). The number of contacts that can be used is practically limited by the leakage current through the diodes. With proper design 20 or more discrete points could be attained. It is also possible to have several logical circuits properly interconnected with each other to reduce the number of inputs into each logical circuit. In the unit shown, the key and the switch panel have the same logical layout. The layout of the switch panel can be wired differently such as the mirror image or any other pattern. It is also possible for the signal from one switch to be used for comparison with more than one point on the keyway or vice versa.

The design of the insert depends on the electrical logic and mechanical layout of the switch panel and can be of any form so that it can set a combination. Depending on the design, the insert can be electrically conducting or nonconducting. The insert can also be of the same shape and form of the key and set the combination by being turned in a slot that has the switches within it that are set up to be depressed in this manner.

The key can be turned to make electrical contact by pressing against leaf springs as well as making contact by just being inserted into a keyway. Small magnets in the key and/or insert can be used to set these electrical switches or contacts. Depending on the design, switches can replace contacts and vice versa. The key and keyway can be of most any design such as rectangular, circular, cylindrical, etc. The key and keyway can also be slotted so that the key can only be inserted one way into the keyway.

FIG. 2 shows a circuit with a negative ground and a switch 2 that is closed by two contacts in the keyway of FIG. 7. If switches 24, 25, 26, 27, 28, or 29 (any combination) of FIG. 2 are depressed, a positive potential of proper magnitude must be impressed on points 4, 5, 6, 7, 8, or 9, respectively, for the output to activate. It should be understood that this circuit is but one workable design. The key and keyway can be designed so that a mechanical switch is depressed (closing the electrical circuit) when the key is fully inserted into the keyway. This would eliminate points 101 and 105 of FIG. 7. The switch can be of the type that has multiple poles and therefore able to lose several points in the circuit simultaneously. The circuit can'also be designed with a positive ground. The keyway frame can be grounded, and insertion of the key into the keyway will cause the contact points to be grounded whenever the key has a discrete point (the circuit can be designed to work under that condition). In this manner only ground potential is brought out on the key. A thwart relay an be used to open the circuit if any tampering is done on the keyway. This relay could be reset when the proper key is inserted into the keyway (similar to the alarm circuit). The relays shown in the diagrams can be replaced by electronics if desired. The battery can be replaced by any suitable power source with proper rectification, voltage, and power.

A time-generated combination can be designed where several (or all) of the insert switches or contacts can be set by a timing mechanism. The proper key that would open this device would change with time.

In hotels or motels this device would be designed so that there is an external switch in the main office that would open the door. This switch would be wired directly to the output circuit, bypassing the logic circuit. This can facilitate cleaning the room and allowing entrance in case of loss of key.

Although the present invention has been described in conjunction with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Such modifications nd variations are considered to be within the purview of the invention and appended claims.

Having thus described my invention.

lclaim:

1. An electronically controlled assembly associated with a solenoid whereby only those who carry a passkey having a predetermined profile may activate the solenoid, said assembly comprising:

A. an electrically conductive passkey having edge notches ,therein creating lateral extensions to define a predetermined profile.

B. a keyway mounted at a position accessible to key holders to receive said passkey, said keyway having an array of discrete electrical contacts therein which are selectively interconnected by the corresponding lateral extensions of a passkey inserted therein in accordance with the profile thereof,

C. a logic circuit connected to said array of contacts to establish an electrical test pattern whose nature depends on which contacts in said array are interconnected by the inserted passkey, said logic circuit including a nonremovable switching panel having a set of electrical switches operable in conjunction with an insertable coded reference key having a profile defined by edge notches creating lateral extensions adapted to actuate switches in said set in registration therewith to produce an electrical reference pattern in accordance with the key code, and means to compare the test and reference patterns to produce a control signal only when the patterns match each other, said coded reference key having a profile which effectively conforms to the profile of the passkey producing test pattern matching the reference pattern pattern, and

D. means responsive to said control signal to produce an output signal and to apply said output signal to said solenoid to activate same whereby said solenoid may be activated only by one in possession of a passkey producing a match with the operative reference key. 

1. An electronically controlled assembly associated with a solenoid whereby only those who carry a passkey having a predetermined profile may activate the solenoid, said assembly comprising: A. an electrically conductive passkey having edge notches therein creating lateral extensions to define a predetermined profile. B. a keyway mounted at a position accessible to key holders to receive said passkey, said keyway having an array of discrete electrical contacts therein which are selectively interconnected by the corresponding lateral extensions of a passkey inserted therein in accordance with the profile thereof, C. a logic circuit connected to said array of contacts to establish an electrical test pattern whose nature depends on which contacts in said array are interconnected by the inserted passkey, said logic circuit including a nonremovable switching panel having a set of electrical switches operable in conjunction with an insertable coded reference key having a profile defined by edge notches creating lateral extensions adapted to actuate switches in said set in registration therewith to produce an electrical reference pattern in accordance with the key code, and means to compare the test and reference patterns to produce a control signal only when the patterns match each other, said coded reference key having a profile which effectively conforms to the profile of the passkey producing test pattern matching the reference pattern pattern, and D. means responsive to said control signal to produce an output signal and to apply said output signal to said solenoid to activate same whereby said solenoid may be activated only by one in possession of a passkey producing a match with the operative reference key. 